<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
    <title></title>

</head>
<body>
<table>
    <tr>
        <td><img src="" /></td>
        <td colSpan="3">购物简易计算器</td>
    </tr>
    <tr>
        <td>第一个数</td>
        <td colSpan="3">
            <input type="text" id="num1Id" />
        </td>
    </tr>
    <tr>
        <td>第二个数</td>
        <td colSpan="3">
            <input type="text" id="num2Id" />
        </td>
    </tr>
    <tr>
        <td>
            <input type="button" value=" + " onclick="cal('+')"/>
        </td>
        <td>
            <input type="button" value=" - " onclick="cal('-')"/>
        </td>
        <td>
            <input type="button" value=" * " onclick="cal('*')"/>
        </td>
        <td>
            <input type="button" value=" / " onclick="cal('/')"/>
        </td>
    </tr>
    <tr>
        <td>计算结果</td>
        <td colSpan="3">
            <input  type="text" id="resultId" />
        </td>
    </tr>
</table>

<script type="text/javascript">
    function cal(type) {
        var num1 = document.getElementById('num1Id').value;
        var num2 = document.getElementById('num2Id').value;
        var result = eval(parseInt(num1) + type + parseInt(num2));
        var resultObj = document.getElementById('resultId');
        resultObj.value = result;
    }


    function cal1(type) {
        var num1 = document.getElementById('num1Id').value;
        var num2 = document.getElementById('num2Id').value;
        var result = 0;
        switch (type) {
            case '+':
                result = parseInt(num1) + parseInt(num2);
                break;
            case '-':
                result = parseInt(num1) - parseInt(num2);
                break;
            case '*':
                result = parseInt(num1) * parseInt(num2);
                break;
            case '/':
                result = parseInt(num1) / parseInt(num2);
                break;
        }
        var resultObj = document.getElementById('resultId');
        resultObj.value = result;
    }

    function add() {
        var num1 = document.getElementById('num1Id').value;
        var num2 = document.getElementById('num2Id').value;
        var result = parseInt(num1) + parseInt(num2);
        var resultObj = document.getElementById('resultId');
        resultObj.value = result;
    }

    function sub() {
        var num1 = document.getElementById('num1Id').value;
        var num2 = document.getElementById('num2Id').value;
        var result = parseInt(num1) - parseInt(num2);
        var resultObj = document.getElementById('resultId');
        resultObj.value = result;
    }

    function mul() {
        var num1 = document.getElementById('num1Id').value;
        var num2 = document.getElementById('num2Id').value;
        var result = parseInt(num1) * parseInt(num2);
        var resultObj = document.getElementById('resultId');
        resultObj.value = result;
    }

    function div() {
        var num1 = document.getElementById('num1Id').value;
        var num2 = document.getElementById('num2Id').value;
        var result = parseInt(num1) / parseInt(num2);
        var resultObj = document.getElementById('resultId');
        resultObj.value = result;
    }
</script>
</body>
</html>